From DariaWiki

Angel is a Mary Sue/self-insert character in several Daria fan works. The creation of author Angelinhel, Angel made her first appearance in "An Angel Named Mary Sue." She is also used as a character in the works "To Understand", "Graduation", "Dear Stacy" and the collaborative work between Angelinhel and The Angst Guy, "Illusions." She also makes a cameo appearance in "Where's Mary Sue When You Need Her?" by Scissors MacGillicutty.

The character appears as a sort of "higher power" or minor deity, with the ability to control the universe (or "plane") in which the story is set. This ability to manipulate Daria's world creates some interesting effects on the characters involved in the story. Though often thought of as an angel by the characters to whom she appears, Angel's sinister actions are often more suited to a devil or demon.

She is usually described as short with long blonde hair and yellow-green eyes. Most often she wears a pair of blue jeans and a gray t-shirt and no shoes.

Angel is usually not named as such in the stories and is simply referred to as "the woman."